Systems and methods for a piezoelectric diaphragm transducer for automotive microphone applications

ABSTRACT

Systems and methods for a transducer assembly for a vehicle having a resonating surface. The transducer assembly comprising a housing, a spacer connected to the housing, and a piezoelectric assembly disposed between the spacer and the housing. The spacer is configured to connect to the resonating surface to form an air gap between the resonating surface and the piezoelectric assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is a divisional of and claims priority to and thebenefit of U.S. application Ser. No. 16/879,147, which claims priorityto and the benefit of (i) U.S. Provisional Application No. 62/895,772,filed Sep. 4, 2019, (ii) U.S. Provisional Application No. 62/939,979,filed Nov. 25, 2019, and (iii) U.S. Provisional Application No.62/988,625, filed Mar. 12, 2020, all of which are hereby incorporated byreference herein in their entireties.

BACKGROUND

Traditional microphones are used in automotive control systems toprovide input for various automotive operations. Traditionalmicrophones, however, may be susceptible to weather conditions whenconfigured outside of a vehicle. More so, traditional microphones may besusceptible to environmental conditions, such as heat or cold, whenconfigured in certain locations on a vehicle, such as in the enginecompartment. Therefore, there is a need for a more robust assemblycapable of functioning as a microphone for a vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is set forth with reference to the accompanyingdrawings. The use of the same reference numerals may indicate similar oridentical items. Various embodiments may utilize elements and/orcomponents other than those illustrated in the drawings, and someelements and/or components may not be present in various embodiments.Elements and/or components in the figures are not necessarily drawn toscale. Throughout this disclosure, depending on the context, singularand plural terminology may be used interchangeably.

FIG. 1 depicts a piezoelectric diaphragm transducer apparatus adhered toa resonating surface according to example embodiments of the presentdisclosure.

FIG. 2 depicts a piezoelectric diaphragm transducer apparatus adhered toa resonating surface having a printed circuit board (PCB) configured asa tunable mass according to example embodiments of the presentdisclosure.

FIG. 3 depicts a piezoelectric diaphragm transducer apparatus adhered toa resonating surface having a PCB integrated within a housing wall ofthe apparatus according to example embodiments of the presentdisclosure.

FIG. 4A depicts a piezoelectric diaphragm transducer apparatus adheredto a resonating surface, where the piezoelectric transducer apparatusincludes a PCB integrated within an electrically shielded housing wallof the apparatus according to example embodiments of the presentdisclosure.

FIG. 4B depicts a piezoelectric diaphragm transducer apparatus adheredto a resonating surface, where the piezoelectric transducer apparatusincludes a two-piece housing and annular ring configuration according toexample embodiments of the present disclosure.

FIG. 5 schematically depicts an example PCB circuit for any one of theapparatuses depicted in FIGS. 1-4B according to example embodiments ofthe present disclosure.

FIG. 6 is a view of a rigid connection surface for a flexible diaphragmportion of the apparatus according to example embodiments of the presentdisclosure.

FIG. 7 is a schematic of an example vehicle control system configured toreceive a sound input signal from the apparatus(s) depicted in any oneof FIGS. 1-5 in accordance with the present disclosure.

FIG. 8A is a front view of a rear-view mirror with a transducer assemblyadhered to an inside surface of the mirror glass according toembodiments of the present disclosure.

FIG. 8B is a partial section view of the rear-view mirror of FIG. 8A inaccordance with embodiments of the present disclosure.

FIG. 9 depicts example transducer assemblies rigidly adhered to vehiclesurfaces, according to example embodiments of the present disclosure.

FIG. 10 shows a section view of one example configuration for attachinga transducer assembly to an exterior surface of automotive glass beneatha glass bezel of a vehicle, according to an embodiment of the presentdisclosure.

FIG. 11A depicts an exploded view of a piezoelectric diaphragmtransducer apparatus according to example embodiments of the presentdisclosure.

FIG. 11B depicts a section view of a piezoelectric diaphragm transducerapparatus according to example embodiments of the present disclosure.

DETAILED DESCRIPTION Overview

Systems and methods for a transducer assembly for a vehicle having aresonating surface (such as a window or other vehicle surface) aredescribed herein. In some instances, the transducer assembly may includea piezo crystal accelerometer configured as an input device fortransforming sound related vibratory input from a rigid resonatingsurface of the vehicle into an electrical output. The output may includea sound signal that may be processed into a recreation of the originalsound using a processing computer, such as, for example, a voicerecognition system associated with an automotive computer of thevehicle. One example embodiment includes a mountable, acousticallyefficient transducer assembly that can capture sound from a vehicleexterior with sound quality sufficient for voice recognition processingusing the onboard computer systems, while having a relatively low noiseprofile associated with the signal.

The transducer assembly may be configured to act as a weather-resistantsolid-state microphone device that is mountable on a vehicle interior orexterior and in locations that may normally/typically be unsuitable formicrophones or other input devices, such as the engine compartment. Thetransducer assembly may include a piezoelectric actuator, such as thetype conventionally used in small consumer electronics to produce beeps,chirps, or other sound output. The piezoelectric actuator may beconfigured as an input device, where the transducer assembly is rigidlymountable to the resonating surface, such as an automobile window, anduses the window to receive sound vibrations and produce a sound signalfor processing by the automotive computer.

In some instances, the transducer assembly may include a small cavitybetween the piezoelectric device and the glass surface upon which thetransducer assembly is mounted. The air gap formed by the cavity mayreceive kinetic movements caused by sound resonating through the glass.The piezoelectric element may receive these kinetic (in some instancesminute) movements via the air gap between the piezoelectric element andthe resonating glass surface, such that the piezoelectric element maymove freely responsive to the kinetic movements. The piezoelectricelement may sense vibration associated with sound (e.g., a personspeaking, a dog barking, an engine noise, a street noise, etc.), as thesound resonates through the mounting surface (e.g., the automotiveglass) and moves the piezoelectric element, which produces a signaloutput without interference from a contacting surface that spans acrossthe entire bottom of the piezoelectric element.

In this manner, the piezoelectric element may be disposed on a flexiblediaphragm suspended just above the air gap by way of a connectingsurface (such as a spacer) that extends around a periphery of theflexible diaphragm. The rigid piezoelectric disk portion may receive theair pressure differential forces from the physical manifestation ofsound as it propagates through the resonant surface. The piezoelectricelement may generate an electrical impulse, which may be conditioned byway of bandpass filters and amplification circuits. The outputs mayinclude a conditioned electric sound signal that may be usable byprocessing computers onboard the vehicle.

The transducer assembly may be electrically passive, such that it ismountable to an exterior vehicle surface and generates a low voltagesignal having negligible electromagnetic interference that wouldotherwise distort or interrupt a sound output signal. For example, thetransducer assembly may include electromagnetic shielding in theassembly housing that is configured to shield the low-voltage signalsfrom crosstalk between the device and other electromagnetic forces.

The systems and methods described hereafter may provide aweather-resistant and robust sound input apparatus for deliveringhigh-quality sound output signals that mimic a microphone, while using arobust and inexpensive package of solid-state components. These andother advantages of the present disclosure are provided in greaterdetail herein.

Illustrative Embodiments

The disclosure will be described more fully hereinafter with referenceto the accompanying drawings, in which exemplary embodiments of thedisclosure are shown, and not intended to be limiting.

FIG. 1 depicts a transducer assembly 100 according to exampleembodiments of the present disclosure. The transducer assembly 100 mayinclude a transducer housing 102 and an annular spacer 112 configured torigidly connect with a resonating surface 116 by way of an adhesivelayer 114 at the base of the annular spacer 112. The transducer assembly100 may further include a flexible diaphragm 136 that divides aninterior portion 106 from a cavity 109 formed by the annular spacer 112when the annular spacer 112 is rigidly disposed in connection with anexterior portion 148 of the resonating surface 116. The flexiblediaphragm 136 may therefore be suspended above the resonating surface116 such that an air gap 144 is formed between the flexible diaphragm136 and the resonating surface 116. Although depicted as generallydome-shaped, it is possible that the housing and general shape of thetransducer assembly 100 may be configured as generally rectangular,ovaloid, or another suitable shape.

In one embodiment, a piezoelectric disk assembly 133 may include theflexible diaphragm 136 and a piezoelectric disk portion 134. Thepiezoelectric disk portion 134 may be rigidly disposed on aninterior-facing side of the flexible diaphragm 136 (e.g., on theinterior portion 106 side of the flexible diaphragm 136). Thepiezoelectric disk assembly 133 may further include a tunable mass 138disposed on a top surface of the piezoelectric disk portion 134. Thetunable mass 138 may rigidly connect with the top surface of thepiezoelectric disk portion 134 and be sized to a mass that can providevibrational enhancement to the piezoelectric disk portion 134. In someinstances, the tunable mass 138 may be configured to accentuate movementcaused by sound resonating through the resonating surface and throughthe annular spacer 112 to the flexible diaphragm 136.

Those skilled in the art will appreciate that a tunable mass may besized, shaped, and oriented within a transducer assembly, where thesize, shape, and orientation are based on experimental observation ofhow these characteristics may affect the system response. Theorientation, shape, size, substrate material, density, and fasteningmeans of the tunable mass may be selected so as to enhance vibratorycomponents of the movable member in the transducer assembly 100 byincreasing an amplitude of the signal output by the piezoelectric diskportion 134 (and the transducer assembly 100 in general).

The transducer assembly 100 may further include an electromagnetic field(EMF) shield layer 118 disposed on a housing interior surface 108 suchthat the interior portion 106 has electromagnetic separation from anexterior portion 104 of the transducer assembly 100 and the interiorportion 106. The EMF shield layer may include and/or be constructed ofconductive or magnetic materials that can electrically isolate a printedcircuit board (PCB) 120, connecting wires 122, 124, and 126, and thepiezoelectric disk portion 134 from radio frequency electromagneticradiation. For example, the EMF shield layer 118 may be constructed ofsheet metal, metal foil, metallic ink, magnetic material, or anothersuitable material.

In some instances, the housing 102 and the EMG shield layer 118 may beintegrated as a single unit where the EMF shield layer 118 isover-molded as an insert during an injection mold operation. In otherinstances, the EMG shield layer 118 may be adhered to the housinginterior surface 108 using fastening means that provide a rigidconnection between the EMF shield layer 118 and the housing 102. The EMFshield layer and the housing 102 may be, alternatively, integrated asthe same part such that the EMF shielding 118 is an additive componentof the thermoplastic used to mold the housing 102 (e.g., a magnetic ormetallic powder, etc.). The EMG shield layer 118 may reduce and/orsubstantially remove the coupling of radio waves, electromagneticfields, and/or electrostatic fields to the signal output of the PCB 120.

The printed circuit board (PCB) 120 of the transducer assembly 100 maybe configured to include one or more signal conditioning circuits thatremove signal content that could interfere with output processing. Theone or more signal conditioning circuits may also be configured toamplify signal output voltages for transmission to an automotivecomputer or the like. An example circuit for the PCB 120 is discussedbelow with reference to FIG. 5.

Various configurations for placement of the PCB 120 are discussed inFIGS. 1-4, which may provide various benefits, including simplificationof the assembly, cost reduction, and longevity of the apparatus whenused in the field. For example, FIG. 1 depicts the PCB 120 disposed onthe interior portion 106 side of the EMF shield layer 118. In FIG. 2, aPCB 220 is shown disposed on a top surface of a piezoelectric diskportion 234 (in place of the tunable mass, where the PCB 220 is weightedaccording to the particular application to function also as the tunablemass). In FIG. 3, a PCB 320 is integrated into a housing 302 of atransducer assembly 300, where the housing 302 may include EMF shieldingmaterial as an additive molding component and/or where the PCB 320 issandwiched between the housing 302 and an EMF shield layer 318. In FIG.4, a PCB 420 may be insert molded into an EMF shield layer 418, wherethe EMF shield layer 418 is a separate layer that is rigidly disposed inconnection with a housing 402.

Although the advantages for these various configurations are discussedin greater detail in FIGS. 2, 3, and 4, respectively, it should beappreciated that in all examples, the PCB may be disposed incommunication with an automotive computer or the like by way of a wiringharness 130 or the like, as depicted in FIG. 1. For example, the wiringharness 130 may be connectible with the automotive computer. In someinstances, the wiring harness 130 may include and/or be a pigtail-less,male, two-pin connector to prevent loose wiring from a pigtail that hasthe potential to vibrate against adjacent members during vehicle motion.Mechanical contact can be perceived as structure-borne sound and mayoverload the output signal transmitted from the transducer assembly 100via the pigtail. Accordingly, the wiring harness 130 may include harnessterminals 128 for removably connecting the connector 132 andelectrically connecting the PCB 120 with the automotive computer. Theharness terminals 128 may connect with the PCB 120 via the connectingwires 126. The PCB 120 may receive sensor data from the piezoelectricdisk assembly 133 by way of the connecting wires 122 and 124.

The transducer assembly 100 is configured such that the annular spacer112 creates the air gap 144 between the piezoelectric disk assembly 133and the resonating surface 116. The annular spacer 112 may be agenerally cylindrical spacing ring that can be constructed from a rigidmaterial having relatively low damping characteristics, such as, forexample, a rigid polymer, a rigid polymer having a fiber, glass, orother additive, metal, or other suitable material, that allows efficientvibration transfer from the resonating surface 116 to reach thepiezoelectric disk assembly 133. Using softer materials for the annularspacer 112 may attenuate the structure-borne vibration signal and reducethe electrical output and increase noise. The annular spacer may spacethe assembly housing 102 and flexible diaphragm 136 apart from themounting surface (e.g., the automotive glass, represented by theresonating surface 116) by creating the air gap between the glass (e.g.,resonating surface 116) and the piezoelectric disk portion 134.

The flexible diaphragm 136 may be constructed of an elasticallydeformable material, such as, for example, copper, nickel alloy, oranother suitable material. In one aspect, portions of the piezoelectricdisk assembly 133 may be a commercially available device, such as apiezoelectric diaphragm that may be used commercially as a sound outputdevice for electronics, such as clocks, calculators, digital cameras,alarm systems, etc. For example, the flexible diaphragm 136, thepiezoelectric disk portion 134, and the connecting wires 122 and 124 maybe commercially available and inexpensive piezoelectric diaphragm sounddevices that are frequently used for sound generation in electronics.

The piezoelectric disk assembly 133 may be configured above theresonating surface 116 with the air gap 144 separating the diaphragmfrom the resonating surface 116. By mounting the piezoelectric diskassembly 133 to the annular spacer 112 at a rigidly connected annularedge 140, a rigid connection surface 142 may form part of the enclosedair gap 144 that increases the sensitivity of the piezoelectric diskportion 134 as it responds to kinetic input (e.g., vibration with sound)resonating through the resonating surface 116.

In some instances, the piezoelectric disk assembly 133 may include acommercially available piezoelectric sound component rigidly fixed tothe annular spacer 112 with fastening means, such as, for example, adouble-sided adhesive layer, epoxy, or a mechanical connection by way ofa press fit between the rigid connection surface 142 and an annularbottom edge of the EMF shield layer 118.

The annular spacer 112 may be separate from the housing 102. That is,the annular spacer 112 may connect to the housing 102 using a snap fitfeature that rigidly fastens the annular spacer 112 to the housing 102such that the piezoelectric disk assembly 133 is sandwiched between thetwo mating parts. Other means for connection are possible and arecontemplated. Regardless of the method of connecting the annular spacer112, the housing 102, and the piezoelectric disk assembly 133, it shouldbe appreciated that the connecting means provide the rigid connectingsurface 142 at a periphery of the flexible diaphragm 136 at an outeredge, such that the diaphragm 136 is distanced from the mounting surfaceof the resonating surface 116. These features may create the secureconnections for transmitting vibratory signals to the piezoelectric diskportion 134, with enhanced sensitivity by way of the air pressuredifferential associated with the vibrations acting on the air gap 144.In some instances, the housing and the spacer may be a single unitarycomponent.

The adhesive layer 114 and the rigid connection surface 142 (which mayalso be an adhesive layer) may provide rigid connection between theflexible diaphragm 136, the annular spacer 112, and the resonatingsurface 116. The adhesive layer 114 (and in some embodiments, the rigidconnecting surface 142) may include fastening means, such as, forexample, a commercially known permanent double-sided adhesive material,an epoxy bonding agent, a fastener (e.g., screws/bolts) or another meansfor providing the rigid connection between the flexible diaphragm 136,the annular spacer 112, and the resonating surface 116.

The bottom portion of the transducer assembly 100 may be mounted to theresonating surface 116 (which may be, in some embodiments, automotivewindow glass). It should be appreciated that sensitivity and longevityof the transducer assembly 100 may be enhanced by a corresponding shapeor indention in the resonating surface 116 such that a cup-shaped dishwithin the glass surface provides a receiving surface upon which thetransducer assembly 100 may be mounted. For example, the mountingsurface may be shaped like a flat circular donut or ring.

The PCB 120 may provide band pass filtering via one or more bypassfilters and signal amplification via one or more amplification circuitsthat can filter the signal output and enhance desired frequenciescentered on the human voice (e.g., about 150 Hz to about 8 kHz). The PCB120 may also provide high pass filtering that can reduce the influenceof any rigid body motion or vibration associated with vehicle movementby reducing the dynamic range of the structure-borne signal. The PCB 120may include one or more op-amps that increase the voltage output of thetransducer assembly 100, powered by a phantom voltage charge (similar tothose used on traditional ECM microphone circuits), which may increasethe signal strength before it travels down through the wiring harness130 to an automatic speech recognition system associated with anautomotive computer.

The wiring harness 130 may be integrated with the housing 102 such thatthe harness and the housing 102 are molded as a single unit, havinginsert molded harness terminals 128 wired in connection with the PCB120. In another example, the PCB 120 may connect with the wiring harness130 and the harness terminals 128 by way of the connecting wires 126that extend through openings in the housing 102 for the wires to passthrough to the exterior surface 110 and connect with the harnessterminals 128. In such instances, the wiring harness 130 may be aseparate component rigidly fastened to the exterior surface 110 of thehousing 102 using fastening means, such as an adhesive, plastic welding,mechanical fasteners, or other suitable means.

The connector 132 may provide connection between the PCB 120 and theautomotive computer. In some instances, the piezoelectric diaphragmtransducer assembly 100 may be configured to have a low profile andsmall package size such that it may be discretely packaged at an edge ofan automotive window glass, behind door trim of the automobile, or inanother area such that the transducer is completely out of view of thecustomer. The package may take a low profile (e.g., no more than 20 mmhigh) and may be configured to include sufficient clearance between theexterior surface 110 of the transducer assembly 100 and any adjacentcomponents of the automobile. Example clearance may be, for example, atleast 5 to 10 mm clearance from any surrounding door trim or othercomponent when installed to provide adequate protection from vibratorysignal noise and to provide protection from unintended structure-bornenoises that may pollute the window microphone signal.

FIG. 2 depicts another example piezoelectric diaphragm transducer 200adhered to the resonating surface 116. Except where expressly describedin the following paragraphs, the transducer assembly 200 may besubstantially similar or identical to the transducer assembly 100 asshown in FIG. 1. For example, the transducer assembly 200, as shown inFIG. 2, may differ from the assembly 100 of FIG. 1 in that apiezoelectric disk assembly 233 may be comprised of a piezoelectric diskportion 234, a flexible diaphragm 236, and the PCB 220, of which thepiezoelectric disk portion 234 and the PCB 220 are rigidly connected toa top surface of the flexible diaphragm 236. The flexible diaphragm 236may be substantially similar or identical to the flexible diaphragm 136described with respect to FIG. 1. The piezoelectric disk portion 234 mayalso be substantially similar or identical to the piezoelectric diskportion 134 of FIG. 1.

The transducer assembly 200 may configure the PCB 220 to additionallyfunction as a tunable mass (where the tunable mass 138 as shown in FIG.1 is omitted, via weighting the PCB 220 to function as the mass inaddition to a signal conditioning unit). In one aspect, the PCB 220 maybe weighted by varying a size, thickness, material, or othercharacteristic, such that the PCB package size, when disposed within thepiezoelectric disk assembly 233, mimics the size and mass distributionof the tunable mass as described in FIG. 1. Accordingly, the PCB 220 maybe disposed on and rigidly connect with the piezoelectric disk portion234. A connecting wire 222 and a connecting wire 224 may connect the PCB220 with a respective one of the piezoelectric disk portion 234 and theflexible diaphragm 236.

The configuration depicted in FIG. 2 may provide several advantages,including a reduction of the number of parts in the transducer assembly200, which may reduce manufacturing costs, simplify design complexity,and increase part longevity and functional reliability. In otheraspects, by integrating the PCB and the tunable mass into a single unitthat moves with the piezoelectric disk assembly 233, the transducerassembly 200 may experience reduced signal noise from externalvibrations, because the PCB is decoupled from the housing except throughthe flexible diaphragm 236.

FIG. 3 depicts another example piezoelectric diaphragm transducerapparatus (hereafter “transducer assembly 300”) adhered to theresonating surface 116. Except where expressly described in thefollowing paragraphs, the transducer assembly 300 may be substantiallysimilar or identical to the transducer assembly 100 as shown in FIG. 1.For example, the transducer assembly 300 as shown in FIG. 3 may differfrom the assembly 100 of FIG. 1 in that a piezoelectric disk assembly333 may include a piezoelectric disk portion 334, a flexible diaphragm336, and a tunable mass 338. However, in the example embodiment of FIG.3, a PCB 320 may be included as an integrated part of a housing 302. InFIG. 3, an EMF shield layer 318 is depicted. The EMF shield layer 318may be separate from (and rigidly connected with) the assembly housing302, or alternatively, may be integrated with the housing 302 such thatthe EMF shield layer 318 is provided as a property of a molding additiveand not a separate part distinct from the housing 302. In this example,the housing 302 may be constructed of a thermoplastic havingelectromagnetic shielding properties.

In another aspect, the PCB 320 may be sandwiched between the EMF shieldlayer 318 and the housing 302. This example configuration may provideEMF shielding properties that protect the PCB 320 from EMF externalvibrations originating from the exterior surface side of the transducerassembly 300 and may also protect the PCB 320 from EMF originating fromthe interior portion 306 side of the transducer assembly 300. Forexample, EMF vibrations could originate from inside of the vehiclethrough the resonating surface 116 (which may be glass).

The flexible diaphragm 336 may be substantially similar or identical tothe flexible diaphragm 136 described with respect to FIG. 1. Thepiezoelectric disk portion 334 may also be substantially similar oridentical to the piezoelectric disk portion 134 of FIG. 1.

The configuration depicted in FIG. 3 may provide several advantages,including a reduction in parts that are movable in the assembly (whichmay reduce unwanted signal content caused by movement of thecomponents). Other possible advantages may include a reduction ofmanufacturing costs associated with removing design complexity and anincrease in part longevity in the field. In other aspects, byintegrating the PCB to be integral with the housing 302, the transducerassembly 300 may further enhance signal sensitivity and reduced signalnoise from vibrations, because the PCB is integrated with the housing302 without the need for connecting means and the possibility ofmicro-movements associated with physical connection of separate members.

FIG. 4A depicts another example piezoelectric diaphragm transducerapparatus (hereafter “transducer assembly 400”), where the transducerassembly 400 includes a PCB 420 integrated within an electricallyshielded wall of an EMF shield layer 418. Except where expresslydescribed in the following paragraphs, the transducer assembly 400 maybe substantially similar or identical to the transducer assembly 100 asshown in FIG. 1. For example, the transducer assembly 400 as shown inFIG. 4A may differ from the assembly 100 of FIG. 1 in that apiezoelectric disk assembly 433 may include a piezoelectric disk portion434, a flexible diaphragm 436, and a tunable mass 438.

The flexible diaphragm 436 may be substantially similar or identical tothe flexible diaphragm 136 described with respect to FIG. 1. Thepiezoelectric disk portion 434 may also be substantially similar oridentical to the piezoelectric disk portion 134 of FIG. 1.

In one aspect, the PCB 420 may be insert molded with the EMF shieldlayer 418, and the EMF shield layer 418 may be rigidly disposed inconnection with the housing 402.

The configuration depicted in FIG. 4A may provide several advantages,including a reduction of connecting parts in the assembly, which mayreduce manufacturing costs and may provide a reduction in designcomplexity. Fewer connected parts could also increase part longevity andfunctional reliability. In other aspects, by integrating the PCB 420with the housing 402 and/or the EMF shield layer 418, the transducerassembly 400 may enhance signal sensitivity and achieve reduced signalnoise from vibrations, because the PCB is integrated with the housing402 and/or the shield layer 418, without the need for connecting meansand the possibility of micro-movements associated with physicalconnection of separate members.

FIG. 4B depicts another example piezoelectric diaphragm transducerapparatus (hereafter “transducer assembly 401”), where a housing 403 isdisposed rigidly connected with a separate annular ring 412 such thatthe flexible diaphragm 436 is rigidly sandwiched between the twoconnected pieces. Although the transducer assembly 401 is depicted withthe PCB 420 integrated within an electrically shielded wall of an EMFshield layer 418, it is possible to apply the two-piece housing andannular ring configuration of FIG. 4B to any of the configurationsdescribed with respect to FIGS. 1-4A.

Except where expressly described in the following paragraphs, thetransducer assembly 400 may be substantially similar or identical to thetransducer assembly 100 as shown in FIG. 1. For example, the transducerassembly 401 as shown in FIG. 4B may differ from the assembly 100 ofFIG. 1 in that the housing 403 is configured to rigidly connect with anannular ring 412, which may be a separate part from the housing 403, byfastening means, such as, for example, a snap fit with undercut snapfeatures, a press fit, adhesive bonding, fasteners (e.g., screws/bolts)or another fastening means.

The configuration depicted in FIG. 4B may provide several advantagesincluding ease of assembly of the transducer assembly 401, which mayreduce manufacturing costs and may provide a reduction in designcomplexity. In other aspects, by rigidly connecting the housing 403 withthe annular spacer 412 as two separate pieces that rigidly sandwich theflexible diaphragm 436 between the members, a conventional piezoelectricdiaphragm may be transformed from a sound output device into an inputdevice as described herein.

FIG. 5 schematically depicts an example PCB circuit 500 for use with anyone of the apparatuses depicted in FIGS. 1-4B. The PCB circuit 500 caninclude a disc element circuit 505 and a preamp circuit 510. In oneexample, the circuit 500 may include a preamp circuit and bandpassfilter. The bandpass filter may provide an output signal having contentbetween 150 Hz to 8 kHz and omit other signal content. The op-amp mayincrease output voltage such that the circuit 500 may provide a signalto a microphone input circuit 515 having sufficient amplitude to supporta clear and unambiguous output that may be used for voice recognition.

FIG. 6 is an overhead view 6-6 (as noted by the arrows 6-6 in FIG. 1) ofthe flexible diaphragm 136. View 6-6 depicts the rigid connectionsurface disposed about a peripheral edge of the diaphragm 136 (thatmates with the rigidly connected annular edge 140). By connecting theflexible diaphragm 136 at the edges only with a secure connecting meansthat positively transmits vibration to the flexible diaphragm 136, theconnection footprint leaves ample interior space that allows theflexible diaphragm 136 to flex from the air pressure differentialcreated by micro-vibrations through the resonating surface 116.

FIGS. 11A and 11B depict a piezoelectric diaphragm transducer apparatus600, according to example embodiments of the present disclosure. Exceptwhere expressly described in the following paragraphs, the transducerassembly 600 may be substantially similar or identical to the transducerassembly 100 as shown in FIG. 1. In the transducer assembly 600 as shownin FIGS. 11A and 11B, the housing 102 may be connected to the annularspacer 112 via an attachment assembly 602. In some instances, theattachment assembly 602 may not require adhesives to hold thepiezoelectric disk assembly 133 between the housing 102 and the annularspacer 112. Adhesives may cause damping and lessens the vibrationtransfer from the glass to the piezoelectric disk assembly 133. Thus,the lack of adhesives may provide the technical advantage of increasedfunctionality and accuracy of the piezoelectric diaphragm transducerapparatus 600.

The annular spacer 112 may include a slot 604. In some instances, theslot 604 may be annular. For example, the slot 604 may extend around thecircumference of the annular base 112. The slot 604 may be any suitablesized, shape, or configuration. The slot 604 may include a ledge 606 anda wall 608. In some instances, the ledge 606 and the wall 608 may betransverse to each other. The ledge 606 and the wall 608 may be anysuitable size, shape, or configuration. One or more protrusions 610 mayextend from the wall 608. The protrusions 610 may be any suitable size,shape, or configuration.

The housing 102 may include a groove 612. In some instances, the groove612 may be annular. For example, the groove 612 may extend around aninner circumference of the housing 102. The groove 612 may be anysuitable size, shape, or configuration. The groove 612 may include aledge 614 and a wall 616. In some instances, the ledge 614 and the wall616 may be transverse to each other. The ledge 614 and the wall 616 maybe any suitable size, shape, or configuration. One or more channels 618may be disposed within the wall 616. The channels 618 may include anopen end 620 and a closed end 622. In some instances, the channels 618may include a first portion 624 and a second portion 626, which istraverse from the first portion 624. That is, the channels 618 may beL-shaped or the like. The channels 618 may be any suitable size, shape,or configuration.

The slot 604 of the annular spacer 112 and the groove 612 of the housing102 may be configured to mate with each other. That is, the slot 604 andgroove 612 may complement each other. In this manner, the protrusions610 may be configured to mate with the channels 618. For example, aprotrusion 610 may pass into a channel 618 through the open end 620 ofthe channel 618 and move along the first portion 624 of the channel 618when the housing 102 is pressed against the annular spacer 112. Next, asthe housing 102 is rotated, the protrusion 610 may travel along thesecond portion 626 of the channel 618. In some instances, the secondportion 626 of the channel 618 may be angled (e.g., as slight incline)such that the housing 102 is tightened against the annular spacer 112 asthe housing 102 is rotated onto the annular spacer 112. For example, thesecond portion 626 of the channel 618 may be angled away from theannular spacer 112. In this manner, the protrusion 610 may travel alongthe second portion 626 of the channel 618, which may cause theprotrusion 610 to apply greater and greater force against the secondportion 626 of the channel 618 as the protrusion 610 travels further upand into the second portion 626 of the channel 618.

The piezoelectric disk assembly 133 may be disposed between the housing102 and the annular spacer 112. For example, an outer edge 628 of thepiezoelectric disk assembly 133 may be sandwiched (i.e., trapped)between the ledge 606 of the annular spacer 112 and the ledge 614 of thehousing 102. In this manner, the piezoelectric disk assembly 133 may besecured in place without the use of adhesives.

FIG. 7 depicts a schematic of an example vehicle control system 700configured to receive a sound input signal from a transducer assembly745. The transducer assembly 745 may be substantially similar oridentical to any of the transducer assemblies 100, 200, 300, or 400, asdescribed with respect to corresponding FIGS. 1-4B). Although describedhereafter as an autonomous vehicle, the control system 700 that may beconfigured for use in a vehicle 705, which may be an autonomous vehicle,a semi-autonomous vehicle, or a conventionally driven vehicle. Thecontrol system 700 can include a user interface 710, a navigation system715, a communication interface 720, autonomous driving sensors 730, anautonomous mode controller 735, and one or more processing device(s)740. The control system 700 may further include a voice recognitionsystem 755. The transducer assembly 745 may provide input signals to thevoice recognition system 755, which may be configured to interpret theinput signals to a contextualized voice input. In one embodiment, thecontrol system 700 may perform one or more vehicle actions based on theinput, such as starting a drive motor, stopping the vehicle, performingsteering or braking actions, or other vehicle operations.

The user interface 710 may be configured or programmed to presentinformation to a user during operation of the vehicle 705. In oneaspect, the user interface may provide auditory output of the signalreceived from the transducer assembly 745. Moreover, the user interface710 may be configured or programmed to receive user inputs, and thus, itmay be disposed in or on the vehicle 705 such that it may be viewable,audible, or interactive by a passenger or operator. For example, in oneembodiment where the vehicle 705 is a passenger vehicle, the userinterface 710 may be located in the passenger compartment.

The navigation system 715 may be configured and/or programmed todetermine a position of the autonomous vehicle 705. The navigationsystem 715 may include a Global Positioning System (GPS) receiverconfigured or programmed to triangulate the position of the AV 705relative to satellites or terrestrial based transmitter towers. Thenavigation system 715, therefore, may be configured or programmed forwireless communication. The navigation system 715 may be furtherconfigured or programmed to develop routes from a current location to aselected destination, as well as display a map and present drivingdirections to the selected destination via, e.g., the user interface710. In some instances, the navigation system 715 may develop the routeaccording to a user preference. Examples of user preferences may includemaximizing fuel efficiency, reducing travel time, travelling theshortest distance, or the like.

In one aspect, the vehicle control system 700 may be configured toreceive audio data from the piezoelectric diaphragm transducer 750(hereafter “transducer 750”) and perform one or more vehicle operationsbased on the audio data. For example, the vehicle control system 700(hereafter “control system 700”) may receive the audio data, where thedata includes one or more engine or motor sounds indicative of anautomotive maintenance issue that requires imminent attention orservicing. Accordingly, the control system 700 may receive the audiodata, compare the audio data to a database of audio sounds correlatedwith automotive maintenance indications, and determine based on a matchof the audio data to a maintenance indication, that the vehicle requiresimminent maintenance. Responsive to determining that the vehiclerequires imminent maintenance, the control system 700 may control theautonomous mode controller 735 to navigate to a service location orother safe location such that the maintenance issue can be addressed. Inone aspect, the control system 700 may obtain information from thenavigation system 715 and navigate the vehicle 705 to the servicelocation based on the GPS information.

In another aspect, the voice recognition system 755 may receive theaudio data and determine that the audio is indicative of human speech.The control system 700 may cause the voice recognition system 755 torecognize the speech content in the audio data and evaluate the speechcontent for context that indicates an imminent need for a vehiclecontrol action, such as stopping the vehicle, slowing down a velocity ofthe vehicle, steering the vehicle to a side of the road, etc.

The control system 700 may facilitate communication between the driverof the vehicle 705 and another driver. For example, another vehicle maypull up next to the vehicle 705, and the driver of the other vehicle mayinitiate an impromptu communication. The driver of the second vehiclemay attempt to get the attention of the driver of the vehicle 705,perhaps by asking for directions with the hope that their voice is heardthrough the closed window of the vehicle 705. Although the driver, withwindows up, music playing, etc., may not normally be able to hear thesecond driver's communication, the voice recognition system 755 mayreceive the speech input (sound) through the transducer 750, which maybe attached to the automotive glass 760 of the vehicle 705, anddetermine, via the voice recognition system 755, that the speech contentof the sound received from the transducer 750 correlates to a need toplay an audio feed through the audio system of the vehicle 705. Thecontrol system 700 may output the voice signal by way of thecommunication interface 720 and/or the user interface device 710. Inthis example, although the window is up, a clear recreation of theindividual's voice may sound through the vehicle sound system(s) suchthat the driver of the vehicle 705 can clearly hear the question beingasked by the other driver.

In another example, an observer outside of the vehicle may notice thatthe vehicle operator has left an object (e.g., a cup of coffee) on theroof of the vehicle and has inadvertently begun to drive off with thecup of coffee on the roof. The observer may yell, “Driver! Your coffeeis on the roof!” Although the driver may not be able to hear the verbalexpression, the control system 700 may receive the audio data via thetransducer 750, interpret the data to contextualize the speech contentindicating “coffee on the roof,” compare the context to a databaseindicative of actions correlated with particular phrases in context(e.g., “coffee on the roof” correlates to a need to slow down and stopthe vehicle when safely able to do so), and issue vehicle controlcommands to the autonomous mode controller 735 based at least in part onthe correlated action associated with the phrase that was contextualizedby the voice recognition system.

The communication interface 720 may be configured or programmed tofacilitate wired and/or wireless communication between the components ofthe vehicle 705 and other devices, such as a remote server or anothervehicle when using a vehicle-to-vehicle communication protocol. Thecommunication interface 720 may also be configured and/or programmed tocommunicate directly from the vehicle 705 to a mobile device using anynumber of communication protocols such as Bluetooth®, Bluetooth® LowEnergy, or Wi-Fi.

A telematics transceiver 725 may include wireless transmission andcommunication hardware that may be disposed in communication with one ormore transceivers associated with telecommunications towers and otherwireless telecommunications infrastructure. For example, the telematicstransceiver 725 may be configured and/or programmed to receive messagesfrom, and transmit messages to one or more cellular towers associatedwith a telecommunication provider, and/or and a Telematics ServiceDelivery Network (SDN) associated with the vehicle 705. In someexamples, the SDN may establish communication with a mobile device,which may be and/or include a cell phone, a tablet computer, a laptopcomputer, a key fob, or any other electronic device. An internetconnected device such as a PC, Laptop, Notebook, or Wi-Fi connectedmobile device, or another computing device may establish cellularcommunications with the telematics transceiver 725 through the SDN.

The communication interface 720 may also communicate using one or morevehicle-to-vehicle communications technologies. An example of avehicle-to-vehicle communication protocol may include, for example, adedicated short-range communication (DSRC) protocol. Accordingly, thecommunication interface 720 may be configured or programmed to receivemessages from and/or transmit messages to a remote server and/or otherautonomous, semi-autonomous, or manually-driven vehicles. In someaspects, the transducer 750 may generate a sound signal that istransmitted to another vehicle using the vehicle-to-vehiclecommunication protocol.

The autonomous driving sensors 730 may include any number of devicesconfigured or programmed to generate signals that help navigate thevehicle 705 while the vehicle 705 is operating in the autonomous (e.g.,driverless) mode. Examples of autonomous driving sensors 730 may includea radar sensor, a LIDAR sensor, a vision sensor, or the like. Theautonomous driving sensors 730 may help the vehicle 705 “see” theroadway and the vehicle surroundings and/or negotiate various obstacleswhile the vehicle is operating in the autonomous mode.

The autonomous mode controller 735 may be configured or programmed tocontrol one or more vehicle subsystems while the vehicle is operating inthe autonomous mode. Examples of subsystems that may be controlled bythe autonomous mode controller 735 may include one or more systems forcontrolling braking, ignition, steering, acceleration, transmissioncontrol, and/or other control mechanisms. The autonomous mode controller735 may control the subsystems based, at least in part, on signalsgenerated by the autonomous driving sensors 730. It is contemplated thatthe control system 700 may control one or more subsystems usinginformation received from the transducer 750. Example information mayinclude speech data as described above, vehicle sounds indicative of amechanical failure or need for maintenance, emergency situationsindicated by sounds such as, for example, a siren of an emergencyvehicle, and other auditory input.

FIGS. 8A and 8B depict a front view of a rear-view mirror 805 and apartial section view of the rear-view mirror 805, respectively. Therear-view mirror 805 is configured with a piezoelectric diaphragmtransducer 810 (hereafter “transducer assembly 810”) that may receivevibrational input from the rear-view mirror glass 820 of the rear-viewmirror 805, and produce a sound signal that may be used for variouspurposes. The transducer assembly 810 may be substantially similar oridentical to the transducer assembly 100 as described with respect toFIG. 1.

The section view A-A as shown in FIG. 8B depicts the transducer assembly810 on an interior portion 815 of the rear-view mirror 805. Thetransducer assembly 810 is depicted rigidly connected with an insidesurface 825 of the rear-view mirror glass 820. In an example embodiment,the transducer assembly 810 may act as the sound input device for use onan interior surface of a vehicle (e.g., inside of a vehicle similar tothe vehicle 705 as shown in FIG. 7) such that the transducer 810 maycapture sound input through the glass 820, and transmit the sound inputto a connected vehicle computer. The configuration as shown in FIGS. 8Aand 8B may replace or supplement an interior microphone that is oftenconfigured inside the cabin of the vehicle (e.g., where the microphoneis integrated with the rear-view mirror, the sun visor, or at anotherinterior location).

In some aspects, the transducer assembly 810 may be installed on othernon-glass surfaces of a vehicle. For example, FIG. 9 depicts a vehicle905 having example transducer assemblies 910, 915, 920, 925, 930, and935 rigidly adhered to various vehicle surfaces that provide variousrespective benefits as resonating surfaces. The transducer assemblies910-935 may connect with and be disposed in communication with a vehiclecontrol system 940 via a control bus 945. The control system 945 may besubstantially similar or identical to the control system 700 describedwith respect to FIG. 7.

The vehicle control system 940, in some aspects, may connect with thetransducer assembly 910, which may rigidly connect with an exteriorsurface of a vehicle windshield 950 beneath a window bezel 955. Oneadvantage to placing the transducer assembly at a location on thewindshield behind a bezel may include taking advantage of a large areaof the resonating surface (e.g., the windshield 950), which may producehigh quality sound signals that originate from a forward position withrespect to the vehicle 905. Accordingly, the sound may resonate throughthe windshield, with which the transducer assembly 910 may generate anoutput signal.

The control system 905 may be disposed in electrical communication withthe transducer assembly 925 configured on the rear-view mirror of thevehicle 905, which may provide means for sound pickup originating fromthe side or rear of the vehicle 905. Moreover, vocal communication fromindividuals standing outside of the vehicle 905 may be generally levelwith the transducer assemblies 910, 925, 930, 935, etc., such thatvoices are readily received by the resonating surfaces and transducerassemblies attached thereto.

FIG. 10 shows a section view of one example configuration for attachinga transducer assembly 1015 to an exterior surface of automotive glass1005 beneath a glass bezel 1025. The automotive glass 1005 may includean indexed recess 1010 forming a pocket for mounting the transducerassembly 1015. The indexed recess 1010 may provide clearance (e.g.,clearance 1020) between surfaces of the transducer assembly 1015 and anyother vehicle members adjacent to the assembly such as, for example, theglass bezel 1025. Producing clearance may mean that adjacent parts tothe transducer assembly 1015 do not contact the transducer assembly1015. By providing the recess 1010 in the automotive glass 1005, thetransducer assembly 1015 may be installed at locations of the vehiclethat may be out of sight from users and may protect the transducerassembly 1015 from the weather or physical damage due to bumping, etc.It should be appreciated, however, that among the many advantages ofembodiments described herein, the transducer assembly 1015 (and othersimilar transducer assemblies described herein) may function as robustand weather resistant microphones that may be installed on vehicleexterior surfaces because they are generally unaffected by weather,dirt, etc.

In the above disclosure, reference has been made to the accompanyingdrawings, which form a part hereof, which illustrate specificimplementations in which the present disclosure may be practiced. It isunderstood that other implementations may be utilized, and structuralchanges may be made without departing from the scope of the presentdisclosure. References in the specification to “one embodiment,” “anembodiment,” “an example embodiment,” etc., indicate that the embodimentdescribed may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesare not necessarily referring to the same embodiment. Further, when afeature, structure, or characteristic is described in connection with anembodiment, one skilled in the art will recognize such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described.

It should also be understood that the word “example” as used herein isintended to be non-exclusionary and non-limiting in nature. Moreparticularly, the word “exemplary” as used herein indicates one amongseveral examples, and it should be understood that no undue emphasis orpreference is being directed to the particular example being described.

A computer-readable medium (also referred to as a processor-readablemedium) includes any non-transitory (e.g., tangible) medium thatparticipates in providing data (e.g., instructions) that may be read bya computer (e.g., by a processor of a computer). Such a medium may takemany forms, including, but not limited to, non-volatile media andvolatile media. Computing devices may include computer-executableinstructions, where the instructions may be executable by one or morecomputing devices such as those listed above and stored on acomputer-readable medium.

With regard to the processes, systems, methods, heuristics, etc.described herein, it should be understood that, although the steps ofsuch processes, etc. have been described as occurring according to acertain ordered sequence, such processes could be practiced with thedescribed steps performed in an order other than the order describedherein. It further should be understood that certain steps could beperformed simultaneously, that other steps could be added, or thatcertain steps described herein could be omitted. In other words, thedescriptions of processes herein are provided for the purpose ofillustrating various embodiments and should in no way be construed so asto limit the claims.

Accordingly, it is to be understood that the above description isintended to be illustrative and not restrictive. Many embodiments andapplications other than the examples provided would be apparent uponreading the above description. The scope should be determined, not withreference to the above description, but should instead be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled. It is anticipated andintended that future developments will occur in the technologiesdiscussed herein, and that the disclosed systems and methods will beincorporated into such future embodiments. In sum, it should beunderstood that the application is capable of modification andvariation.

All terms used in the claims are intended to be given their ordinarymeanings as understood by those knowledgeable in the technologiesdescribed herein unless an explicit indication to the contrary is madeherein. In particular, use of the singular articles such as “a,” “the,”“said,” etc. should be read to recite one or more of the indicatedelements unless a claim recites an explicit limitation to the contrary.Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments could include, while other embodiments may not include,certain features, elements, and/or steps. Thus, such conditionallanguage is not generally intended to imply that features, elements,and/or steps are in any way required for one or more embodiments.

That which is claimed is:
 1. A transducer assembly for a resonatingsurface, the transducer assembly comprising: a housing having aninterior portion and an exterior portion; a spacer having a proximal endand a distal end, wherein the proximal end is configured to be connectedto the housing and the distal end is configured to be connected to theresonating surface; and a piezoelectric assembly disposed between thespacer and the housing, wherein the piezoelectric assembly is configuredto be attached about the proximal end of the spacer and spaced apartfrom the resonating surface.
 2. The transducer assembly of claim 1,further comprising an air gap formed by the spacer, the piezoelectricassembly, and the resonating surface.
 3. The transducer assembly ofclaim 1, wherein the piezoelectric assembly comprises a diaphragm, apiezoelectric disk disposed on the diaphragm, and a tunable massdisposed on the piezoelectric disk.
 4. The transducer assembly of claim1, further comprising a printed circuit board in communication with thepiezoelectric assembly.
 5. The transducer assembly of claim 4, whereinthe printed circuit board comprises an amplification circuit and abandpass filter, wherein the printed circuit board is configured to:receive, from the piezoelectric assembly, a signal; remove, by thebandpass filter, unwanted signal content; amplify, by the amplificationcircuit, the signal; and transmit the signal.
 6. The transducer assemblyof claim 4, further comprising a harness terminal in communication withthe printed circuit board.
 7. The transducer assembly of claim 1,wherein the spacer is annular.
 8. The transducer assembly of claim 1,wherein the housing and the spacer are unitary.
 9. A method, comprising:attaching a transducer assembly to a resonating surface of a vehicle,the transducer assembly comprising a piezoelectric assembly spaced apartfrom the resonating surface; and receiving, by the piezoelectricassembly, a kinetic vibration resonating from the resonating surface;and generating, by the piezoelectric assembly, an electric output signalassociated with the kinetic vibration.
 10. The method of claim 9,further comprising forming an air gap by a spacer, the piezoelectricassembly, and the resonating surface.
 11. The method of claim 10,wherein the spacer is annular.
 12. The method of claim 9, wherein thepiezoelectric assembly comprises a diaphragm, a piezoelectric diskdisposed on the diaphragm, and a tunable mass disposed on thepiezoelectric disk.
 13. The method of claim 9, further comprising aprinted circuit board in communication with the piezoelectric assembly.14. The method of claim 13, wherein the printed circuit board comprisesan amplification circuit and a bandpass filter, wherein the printedcircuit board is configured to: receive, from the piezoelectricassembly, a signal; remove, by the bandpass filter, unwanted signalcontent; amplify, by the amplification circuit, the signal; and transmitthe signal.
 15. The method of claim 13, further comprising a harnessterminal in communication with the printed circuit board.